Anatomy and physiology critical thinking questions

convergence

A motor neuron in the spinal cord typically receives input from neurons that originate in several different regions of the brain. Is this an example of convergence or divergence?

death, because they would no longer have blood supply

As people age, some osteonic (haversian) canals may become blocked. What effect would this have on the surrounding osteocytes?

*At pH = 6, [H+] = 10−6 mol/L and [OH−] = 10−8 mol/L *6.82 is more acidic *both are 1.41 from a ph of 7

At pH 7 (neutrality), the concentrations of H+ and OH− are equal (10−7 mol/liter). What are the concentrations of H+ and OH− at pH 6? Which pH is more acidic, 6.82 or 6.91? Which pH is closer to neutral, 8.41 or 5.59?

folic acid

Deficiency of which B vitamin is linked to spina bifida?

no

Do all proteins have a quaternary structure?

No, it lowers the activation energy needed

Does a catalyst change the potential energies of the products and reactants?

yes, Insulin promotes insertion of glucose transporter (GluT) in the plasma membrane, which increases cellular glucose uptake by carrier-mediated fa- cilitated diffusion.

Does insulin alter glucose transport by facilitated diffusion?

fatty acid

Does the oxygen in the water molecule removed during dehydration synthesis come from the glycerol or from a fatty acid?

S phase of interphase

During which phase of the cell cycle does DNA replication occur?

sutures are classified as synarthroses because they are immovable; syndesmoses are classified as amphiarthroses because they are slightly movable.

Functionally, why are sutures classified as synarthroses, and syndesmoses as amphiarthroses?

extensor digitorum, gluteus maximus

Give an example of a muscle named for each of the following characteristics: direction of fibers, shape, action, size, origin and insertion, location, and number of tendons of origin.

Yes, because the leak channels would still allow K+ to exit more rapidly than Na+ could enter the axon. Some mammalian myelinated axons have only a few voltage-gated K+ channels.

Given the existence of leak channels for both K+ and Na+, could the membrane repolarize if the voltage-gated K+ channels did not exist?

2 in the first, 4 in the second

How are the electrons of carbon distributed between the first and second electron shells?

At some excitatory synapses, ACh binds to ionotropic receptors with cation channels that open and subsequently generate EPSPs in the postsynaptic cell. At some inhibitory synapses, ACh binds to metabotropic receptors coupled to G proteins that open K+ channels, resulting in the formation of IPSPs in the postsynaptic cell

How can the neurotransmitter acetylcholine (ACh) be excitatory at some synapses and inhibitory at others?

their shape

How did the pyramidal cells get their name?

Schwann -1 only one oligodendrocytes - multiple

How do Schwann cells and oligodendrocytes differ with respect to the number of axons they myelinate?

Medial - towards the midline of the body lateral - away from the midline

How do medial and lateral rotation differ?

they involve receptor proteins

How do receptor-mediated endocytosis and phagocytosis differ from bulk-phase endocytosis?

they have a nonbranched duct

How do simple multicellular exocrine glands differ from compound ones?

entry - receives and modifies proteins from the ER exit - modifies, sorts and packages molecule for transportation

How do the entry and exit faces differ in function?

increase the surface area for chemical reactions and have some enzymes used for ATP production

How do the mitochondrial cristae contribute to its ATP-producing function?

digestive tract > interstitial fluid > cell body

How does a nutrient in the external environment reach a body cell?

facet on the head of a rib fits into a facet or demifacet on the body of a vertebra, and the articular part of the tubercle of a rib articulates with the facet of the transverse process of a vertebra.

How does a rib articulate with a thoracic vertebra?

During anaphase I of meiosis, the paired chromatids are held together by a centromere and do not separate. During anaphase of mitosis, the paired chromatids separate and the centromeres split.

How does anaphase I of meiosis differ from anaphase of mitosis?

The result of crossing-over is that four haploid gametes are genetically unlike each other and genetically unlike the starting cell that produced them.

How does crossing-over affect the genetic content of the haploid gametes?

this is where cell divisions in the zone of proliferating cartilage and replacement of the zone of calcified cartilage with bone (new diaphysis) takes place

How does the epiphyseal (growth) plate account for the lengthwise growth of the diaphysis?

originates at the anteromedial aspect of the floor of the orbit and inserts on the posterolateral aspect of the eyeball.

How does the inferior oblique muscle move the eyeball superiorly and laterally?

activity of the osteoporosis class in the endosteum

How does the medullary cavity enlarge during growth in thickness?

number of double bonds and the types of functional groups attached to ring A.

How is the structure of estradiol different from that of testosterone?

6/12

How many carbon atoms are there in fructose? In sucrose?

4 pairs, nerves and blood vessels pass through these tunnels

How many foramina pierce the sacrum, and what is their function?

Glucose has five OH groups and six carbon atoms.

How many hydroxyl groups does a molecule of glucose have? How many carbon atoms are part of glucose's carbon skeleton?

3

How many points of attachment are there between the radius and ulna?

DNA base sequence AGCT would be transcribed into the mRNA base sequence UCGA by RNA polymerase.

If the DNA template had the base sequence AGCT, what would be the mRNA base sequence, and what enzyme would catalyze DNA transcription?

It can not divide

If you observed that a cell did not have a centrosome, what could you predict about its capacity for cell division?

osteoclasts

If you wanted to develop a drug to lessen the effects of osteoporosis, would you look for a chemical that inhibits the activity of osteoblasts or that of osteoclasts?

2/ 1

In an amino acid, what is the minimum number of carbon atoms? Of nitrogen atoms?

When you adduct your arm or leg, you bring it closer to the midline of the body, thus "adding" it to the trunk.

In what way is considering adduction as "adding your limb to your trunk" an effective learning device?

it doesn't articulate with another bone

In what way is the hyoid bone different from all other bones of the axial skeleton?

liver - epigastric region; ascending colon - right lumbar region; urinary bladder - hypogastric region; small intestine - umbilical region. pain associated with appendicitis - right lower quadrant (RLQ).

In which abdominopelvic region is each of the following found: most of the liver, ascending colon, urinary bladder, and most of the small intestine? In which abdominopelvic quadrant would pain from appendicitis (inflammation of the appendix) be felt?

Urinary bladder = P, stomach = A, heart = T, small intestine = A, lungs = T, internal female reproductive organs = P, thymus = T, spleen = A, liver = A

In which cavities are the following organs located: urinary bladder, stomach, heart, small intestine, lungs, internal female reproductive organs, thymus, spleen, liver? Use the following symbols for your responses: T = thoracic cavity, A = abdominal cavity, or P = pelvic cavity.

cerebral cortex

In which region of the brain does perception primarily occur?

cytosol

Is the concentration of K+ in body cells higher in the cytosol or in the extracellular fluid?

No, distal. No, posterior. Yes.Yes.No, medial

Is the radius proximal to the humerus? Is the esophagus anterior to the trachea? Are the ribs superficial to the lungs? Is the urinary bladder medial to the ascending colon? Is the sternum lateral to the descending colon?

thumb

Muscles of the thenar eminence act on which digit?

sphenoid with the frontal, parietal , temporal, occipital, temporal, parietal, frontal, and back to crest galli

Name the bones that articulate with the sphenoid bone, starting at the crista galli of the ethmoid bone and going in a clockwise direction.

spatial

Suppose that EPSPs summate in a postsynaptic neuron in response to simultaneous stimulation by the neurotransmitters glutamate, serotonin, and acetylcholine released by three separate presynaptic neurons. Is this an example of spatial or temporal summation?

it would make the resting membrane potential more positive

Suppose that the plasma membrane of a neuron has more Na+ leak channels than K+ leak channels. What effect would this have on the resting membrane potential?

No, because water is polar

Table sugar (sucrose) easily dissolves in water but is not an electrolyte. Is it likely that all the covalent bonds between atoms in table sugar are nonpolar bonds? Why or why not?

CaCO3 salt, H2SO4 acid

The compound CaCO3 (calcium carbonate) dissociates into a calcium ion (Ca2+) and a carbonate ion (CO32−). Is it an acid, a base, or a salt? What about H2SO4, which dissociates into two H1 and one SO42−?

sesamoid

The patella is classified as which type of bone? Why?

inside the neuron is more negative then the outside

The resting membrane potential of a neuron typically is −70 mV. What does this mean?

holocrine, and merocrine

To what class of glands do sebaceous (oil) glands belong? Salivary glands?

urinary and digestive system

To which body systems do the organs shown here within the abdominal and pelvic cavities belong?

positively & negatively charged ions

What are cations and anions?

atlanto-axial joints

What are other examples of pivot joints (besides the one shown in this figure)?

Transferrin, vitamins, and hormones

What are several other examples of ligands that can undergo receptor-mediated endocytosis?

muscu- lar contractions, movement of chromosomes, transport of substances across cell membranes, and synthesis (anabolic) reactions.

What are some cellular activities that depend on energy supplied by ATP?

*Epithelial tissue covers the body, lines various structures, and forms glands. *Connective tissue protects, supports, binds organs together, stores energy, and helps provide immunity. *Muscular tissue contracts and generates force and heat. *Nervous tissue detects changes in the environment and generates nerve impulses that activate muscular contraction and glandular secretion.

What are some key differences in function among the four tissue types?

source of thoughts, emotions, and memories; and gives rise to signals that stimulate muscles to contract and glands to secrete.

What are some of the functions of the CNS?

pubic symphysis anteriorly, the coccyx posteriorly, and the walls of the pelvis laterally.

What are the borders of the pelvic diaphragm?

pubic symphysis anteriorly, the coccyx posteriorly, and the ischial tuberosities laterally.

What are the borders of the perineum?

double-stranded molecule of DNA wrapped twice around a core of eight histones (proteins)

What are the components of a nucleosome?

physical support for the epithelial tis- sue and plays a part in growth and wound healing, restriction of molecular movement between tissues, and blood filtration in the kidneys.

What are the functions of the basement membrane?

attaches the lower limbs to the axial skeleton and supports the backbone and pelvic viscera

What are the functions of the bony pelvis?

produce mucus and serve as resonating chambers for vocalizations.

What are the functions of the paranasal sinuses?

chewing, detection of taste, swallowing and speech

What are the functions of the tongue?

incloses the spinal cord, provides space through which spinal nerves can exit

What are the functions of the vertebral and intervertebral foramina?

Upper limb muscles exhibit diversity of movement; lower limb muscles function in stability, locomotion, and maintenance of posture. In addition, lower limb muscles usually cross two joints and act equally on both.

What are the principal differences between the muscles of the free upper and lower limbs?

rough has ribosomes, smooth does not.

What are the structural and functional differences between rough and smooth ER?

superior foramen mangum of the occipital bone, inferior sacral vertebra

What are the superior and inferior boundaries of the spinal dura mater?

hydrolysis by ATPase to activate binding, detachment after power stroke, powers the Ca2+ pump

What are the three functions of ATP in muscle contraction?

secreted by exocytosis, incorporated into the cytoplasm, or occupy storage vesicles to become lysomes

What are the three general destinations for proteins that leave the Golgi complex?

plasma membrane, cytoplasm, and nucleus.

What are the three principal parts of a cell?

flexion of the thumb and lateral flexion of the trunk

What are two examples of flexion that do not occur along the sagittal plane?

intercarpal and intertarsal

What are two examples of joints that permit gliding movements?

Heartbeat, respiration, nerve cell functioning, enzyme functioning, and blood clotting all depend on proper levels of calcium.

What body functions depend on proper levels of Ca2+?

muscle action potential sweeps over the sarcolemma and calcium ions are released from the sarcoplasmic reticulum.

What events occur during the latent period?

depth, extent, age and health of person

What factors determine the seriousness of a burn?

The diameter of an axon, presence or absence of a myelin sheath, and temperature determine the speed of propagation of an action potential.

What factors determine the speed of propagation of an action potential?

they disappear, they do not change

What happens to the I band and H zone as muscle contracts? Do the lengths of the thick and thin filaments change?

a region of contact between two neurons or between a neuron and effector

What is a synapse?

membrane that consists of an epithelial layer and and underlying layer of connective tissue

What is an epithelial membrane?

complex of DNA, proteins and RNA

What is chromatin?

myelin

What is responsible for the white appearance of white matter?

stabilize the hyoid bone to assist in tongue movement

What is the combined action of the suprahyoid and infrahyoid muscles?

secretions from sebaceous glands, sloughed off peridermal cells and hairs

What is the composition of vernix caseosa?

it is the only moving bone in the skull

What is the distinctive functional feature of the mandible among almost all the other skull bones?

more fibers = more forceful contraction

What is the effect of the size of a motor unit on its strength of contraction? (Assume that each muscle fiber can generate about the same amount of tension.)

It relates the protein from the final tRNA

What is the function of a stop codon?

secret fibers and ground substance of extracellular matrix

What is the function of fibroblasts?

protect DNA of keratinocytes from UV damage

What is the function of melanin?

it divides it into right and left sides

What is the function of the nasal septum?

Attach the upper limbs to the pectoral girdle

What is the function of the pectoral girdle?

increase the speed of nerve impulse

What is the functional advantage of myelination?

diarthroses

What is the functional classification of synovial joints?

cilia moves fluid across the surface, flagella moves the cell

What is the functional difference between cilia and flagella?

essential for growth in bone thickness, bone repair, and bone nutrition. It also serves as a point of attachment for ligaments and tendons.

What is the functional significance of the periosteum?

extracellular surface of the plasma membrane consisting of portions of membranes from glycolipids and glycoproteins (carbohydrates).

What is the glycocalyx?

stabilize the scapula and assist in movement of humerous

What is the main action of the muscles that move the pectoral girdle?

ionic bond = loss and gain of electrons; covalent bond = sharing of pairs of electrons.

What is the main difference between an ionic bond and a covalent bond?

negative -reverses the original stimulus postitive - enhances it

What is the main difference between negative and positive feedback systems?

secondary active transport, hydrolysis of ATP is used indirectly to drive the activity of symporter or antiporter proteins; this reaction directly powers the pump protein in primary active transport.

What is the main difference between primary and secondary active transport mechanisms?

pericardium, pleural

What is the name of the cavity that surrounds the heart? Which cavities surround the lungs?

autophagy

What is the name of the process by which worn-out organelles are digested by lysosomes?

relieve joint pain and permit greater range of motion

What is the purpose of arthroplasty?

ATP adds a phosphate group to the pump protein, which changes the pump's three-dimensional shape. ATP transfers energy to power the pump.

What is the role of ATP in the operation of this pump?

provides a regeneration tube that guides regrowth of a severed axon.

What is the role of the neurolemma in regeneration?

it is the course that babies take to be born

What is the significance of the pelvic axis?

synchondrosis is held together by hyaline cartilage, a symphysis is held together by fibrocartilage, and epiphyseal cartilage is a hyaline cartilage growth center during endochondral bone formation.

What is the structural difference between a synchondrosis, symphysis, and epiphyseal cartilage?

allows directional terms to be clearly define

What is the usefulness of defining one standard anatomical position?

depolarizing graded potential (excitatory)/ hyper polarizing graded potential

What kind of graded potential describes a change in membrane potential from −70 to −60 mV? From −70 to −80 mV?

parietal and temporal are joined by squamous, parietal and occipital are joined by the lamboid, parietal and frontal by the coronal

What major bones are joined by (1) the squamous suture, (2) the lambdoid suture, and (3) the coronal suture?

extension at the knee

What movement occurs at the knee joint when the quadriceps femoris (anterior thigh) muscles contract?

protraction

What movement of the shoulder girdles occur when you bring your arms forward until the elbows touch?

medulla oblongata of the brain connects with the spinal cord

What organs of the nervous system join together within the foramen magnum?

perpendicular plate, lateral masses

What part of the ethmoid bone forms the superior part of the nasal septum? The medial walls of the orbits?

motor end plate

What part of the sarcolemma contains acetylcholine receptors?

olecranon

What part of the ulna is called the "elbow"?

tissues that overly bony projections

What parts of the body are usually affected by pressure ulcers?

22.5%

What percentage of the body would be burned if only the anterior trunk and anterior left upper limb were involved?

it depends on blood vessels in connec- tive tissue for oxygen, nutrients, and waste disposal.

What relationship between epithelial tissue and connective tissue is important for the survival and function of epithelial tissues?

P-holds the tRNA attached to the growing polypeptide. A- holds the tRNA carrying the next amino acid to be added to the growing polypeptide.

What roles do the P and A sites serve

Dendrites and the cell body receive input; the axon conducts nerve impulses (action potentials) and transmits the message to another neuron or effector cell by releasing a neurotransmitter at its synaptic end bulbs.

What roles do the dendrites, cell body, and axon play in communication of signals?

arches

What structural feature of the arches allows them to absorb shocks?

plantar aponeurosis

What structure supports the longitudinal arch and encloses the flexor tendons of the foot?

superior and inferior extensor retinacula

What structures firmly hold the tendons of the anterior compartment muscles to the ankle?

Flexor tendons of the digits and wrist and the median nerve

What structures pass deep to the flexor retinaculum?

anti-oxidants - selenium, zinc, beta-carotene, vitamin C, and vitamin E

What substances in the body can inactivate oxygen- derived free radicals?

binding of particles to a plasma membrane receptor

What triggers pseudopod formation?

isometric contractions

What type of contraction occurs in your neck muscles while you are walking?

mechanically gated

What type of gated channel is activated by a touch on the arm?

Hydrolysis

What type of reaction takes place during catabolism of proteins?

Nonpolar, hydrophobic molecules (oxygen, carbon dioxide, and nitrogen gases; fatty acids; steroids; and fat-soluble vitamins) plus small, uncharged polar molecules (water, urea, and small alcohols) move across the lipid bilayer of the plasma membrane through the process of simple diffusion.

What types of molecules move across the lipid bilayer of the plasma membrane via simple diffusion?

epithelial tissue / connective tissue

What types of tissues make up the epidermis and the dermis?

the cross bridges could not detach from actin

What would happen if ATP suddenly were not available after the sarcomere had started to shorten?

they would die out as they spread through the dendrites and cell body

What would happen if summation of graded potentials in a neuron did not occur?

increase - negative feedback system

What would happen to heart rate if some stimulus caused blood pressure to decrease? Would this occur by way of positive or negative feedback?

late anaphase

When does cytokinesis begin?

receptor

When stimulating a cell, the hormone insulin first binds to a protein in the plasma membrane. This action best represents which membrane protein function?

synthesized in the nucleolus, then assembled in the cytoplasm

Where are subunits of ribosomes synthesized and assembled?

perforating interosteonic (perforating or Volkmann's) canals.

Where do periosteal arteries enter bone tissue?

in regions of the cartilage model that will give rise to the epiphysis

Where in the cartilage model do secondary ossification centers develop during endochondral ossification?

Glycolysis, exchange of phosphate between creatine phosphate and ADP, and glycogen breakdown occur in the cytosol. Oxidation of pyruvic acid, amino acids, and fatty acids (aerobic respiration) occurs in mitochondria.

Where inside a skeletal muscle fiber are the events shown here occurring?

triceps brachii, located posterior to there humerous

Where is the belly of the muscle that extends the forearm located?

microglia

Which CNS neuroglia function as phagocytes?

rectus abdominis

Which abdominal muscle aids in urination?

Kyphosis (hunchback)

Which abnormal curve is common in women with advanced osteoporosis?

liver cells and skeletal muscles

Which body cells store glycogen?

parietal

Which bones form the posterior, lateral portion of the cranium?

Flat bones of the skull, most facial bones, the mandible (lower jawbone), and the medial part of the clavicle

Which bones of the body develop by intramembranous ossification?

squamous cells, because they are so thin

Which cell shape is best adapted for the rapid movement of substances from one cell to another?

Voltage-gated Na+ channels are open during the depolarizing phase, and voltage-gated K+ channels are open during the repolarizing phase.

Which channels are open during the depolarizing phase? During the repolarizing phase?

perimysium

Which connective tissue coat surrounds groups of muscle fibers, separating them into fascicles?

thoracic and sacral

Which curves of the adult vertebral column are concave (relative to the anterior side of the body)?

microtubules

Which cytoskeletal component helps form the structure of centuries, cilia and flagella?

stratum basale

Which epidermal layer includes stem cells that continually undergo cell division?

anterolateral fontanel (sphenoidal)

Which fontanel is bordered by four different skull bones?

Hydrogen, carbon, oxygen and nitrogen

Which four of these elements are present most abundantly in living organisms?

interneurons

Which functional class of neurons is responsible for integration?

basal cell carcinoma

Which is the most common type of skin cancer?

masetter

Which is the strongest muscle of mastication?

atlanto-axial joint

Which joint permits you to move your head to signify "no"? Which bones are involved?

tibia

Which leg bone bears the weight of the body?

Organ

Which level of structural organization is composed of two or more different types of tissues that work together to perform a specific function?

lateral

Which ligament prevents displacement of the mandible?

iliofemeral, pubofemoral and ischiofemoral

Which ligaments limit the degree of extension that is possible at the hip joint?

flexion, extension, hyperextension

Which movements are possible at a hinge joint?

flexion, abduction, extension, adduction, and rotation

Which movements in continuous sequence produce circumduction?

diaphragm

Which muscle associated with breathing is innervated by the phrenic nerve?

brachialis is the most powerful forearm flexor; the triceps brachii is the most powerful forearm extensor.

Which muscles are the most powerful flexor and the most powerful extensor of the forearm?

The quadriceps femoris consists of the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius; the hamstrings consist of the biceps femoris, semitendinosus, and semimembranosus.

Which muscles constitute the quadriceps femoris and hamstring muscles?

frowning - corrugated supercilii smile - zygomaticus major pouting - mentalis squinting - orbicularis oculi

Which muscles of facial expression cause frowning, smiling, pouting, and squinting?

splenius muscles

Which muscles originate at the midline and extend laterally and superiorly to their insertions?

DNA: Cytosine, thymine, adenine, and guanine RNA: Cytosine, uracil, adenine, and guanine

Which nitrogenous bases are present in DNA? In RNA?

4-6

Which numbered steps in this figure are part of excitation-contraction coupling?

frontal, parietal, sphenoid, ethmoid, and temporal

Which of the bones shown here are cranial bones?

thick, myofibril, muscle

Which of the following is the smallest: muscle fiber, thick filament, or myofibril? Which is largest?

mesoderm

Which of the three basic embryonic tissues—ectoderm, mesoderm, and endoderm—gives rise to most of the skeletal system?

Hexoses are six-carbon sugars; examples include glucose, fructose, and galactose.

Which of these monosaccharides are hexoses?

myotome

Which part of a somite differentiates into skeletal muscle?

midregion

Which part of the clavicle is its weakest point?

acetabulum and articular surface

Which part of the hip bone articulates with the femur? With the sacrum?

acromion

Which part of the scapula forms the high point of the shoulder?

Ligand-gated channels and mechanically-gated channels can be present in the dendrites of sensory neurons, and ligand-gated channels are numerous in the dendrites and cell bodies of interneurons and motor neurons.

Which parts of a neuron contain mechanically-gated channels? Ligand-gated channels?

*with the capitulum and radial fossa of the humerus *trochlea, coronoid fossa, olecranon fossa

Which parts of the humerus articulate with the radius at the elbow? With the ulna at the elbow?

the facets and demifacets on the vertebral bodies of the thoracic vertebrae articulate with the heads of the ribs, and the facets on the transverse processes of these vertebrae articulate with the tubercles of the ribs.

Which parts of the thoracic vertebrea articulate with the ribs?

parasagittal plane

Which plane divides the brain into unequal right and left portions?

frontal plane

Which plane divides the heart into anterior and posterior portions?

Head is hydrophilic, tail is hydrophobic

Which portion of a phospholipid is hydrophilic, and which portion is hydrophobic?

Z- actin and titin A- myosin, troponin, tropomyosin, and titin I- actin, troponin, tropomyosin, and titin

Which proteins connect into the Z disc? Which proteins are present in the A band? In the I band?

frontal, sphenoid, zygomatic, maxilla, lacrimal, ethmoid, and palatine.

Which seven bones form the orbit?

sarcoplasmic reticulum

Which structure shown here releases calcium ions to trigger muscle contraction?

talus

Which tarsal bone articulates with the tibia and fibula?

flat tendons of the subscapularis, supraspinatus, infraspinatus, and teres minor muscles that form a nearly complete circle around the shoulder joint.

Which tendons make up the rotator cuff?

flat bones

Which type of bone primarily provides protection and a large surface area for muscle attachment?

Gap junctions allow cellular communication via passage of electrical and chemical signals between adjacent cells.

Which type of cell junction functions in communication between adjacent cells?

second class

Which type of lever produces the most force?

multipolar

Which type of neuron shown in this figure is the most abundant type of neuron in the CNS?

visceral - contains gap junctions

Which type of smooth muscle is more like cardiac muscle than skeletal muscle, with respect to both its structure and function?

they are composed of tightly packed, hard keratinized epidermal cells

Why are nails so hard?

Norepinephrine, epinephrine, dopamine, and serotonin are classified as biogenic amines because they are derived from amino acids that have been chemically modified.

Why are norepinephrine, epinephrine, dopamine, and serotonin classified as biogenic amines?

Because it needs to move to the egg, locomotion

Why are sperm the only body cells that need to have a flagellum?

because weight increases toward the ends of the vertebral column

Why are the lumbar vertebrae the largest and strongest in the vertebral column?

because of the structures that lie in their boundaries

Why are triangles of the neck important?

because it bears the most weight

Why do most herniated discs occur in the lumbar region?

because the loop will continue unless something stops it

Why do positive feedback systems that are part of a normal physiological response include some mechanism that terminates the system?

A stronger stimulus opens more mechanically-gated channels or ligand- gated channels than a weaker stimulus.

Why does a stronger stimulus cause a larger graded potential than a weaker stimulus?

plucking stimulates the hair root plexus which have pain receptors

Why does it hurt when you pluck out a hair but not when you have a haircut?

because calcium and phosphorus deposition is a slow process, and bone cells generally grow and reproduce slowly.

Why does it sometimes take months for a fracture to heal?

looseness of its articular capsule and shallowness of the glenoid cavity

Why does the shoulder joint have more freedom of movement than any other joint of the body?

because the product needs to match the reactants

Why does this reaction require two molecules of H2?

development, maintenance and repair of bone

Why is bone resorption important?

Sucrase has specificity for the sucrose molecule and thus would not "recognize" glucose and fructose.

Why is it that sucrase cannot catalyze the formation of sucrose from glucose and fructose?

A sarcomere length of 2.2 μm gives a generous zone of overlap between the parts of the thick filaments that have myosin heads and the thin filaments without the overlap being so extensive that sarcomere shortening is limited

Why is tension maximal at a sarcomere length of 2.2 μm?

because the female pelvis is broader

Why is the angle of convergence of the femurs greater in females than males?

energy is release from the reactants resulting in a lower potential energy of the product

Why is the reaction illustrated here exergonic?

in some electrical synapses (gap junctions), ions may flow equally well in either direction, so either neuron may be the presynaptic one. At a chemical synapse, one neuron releases neurotransmitter and the other neuron has receptors that bind this chemical. Thus, the signal can proceed in only one direction.

Why may electrical synapses work in two directions, but chemical synapses can transmit a signal in only one direction?

So that each new cell has a complete genome

Why must DNA replication occur before cytokinesis in somatic cell division?

The N atom in ammonia is electronegative. Because it attracts electrons more strongly than do the H atoms, the nitrogen end of ammonia acquires a slight negative charge, allowing H atoms in water molecules (or in other am- monia molecules) to form hydrogen bonds with it. Likewise, O atoms in water molecules can form hydrogen bonds with H atoms in ammonia molecules.

Why would you expect ammonia (NH3) to form hydrogen bonds with water molecules?

crenation because it is hypertonic

Will a 2% solution of NaCl cause hemolysis or crenation of RBCs? Why?

An action potential will not occur in response to a hyperpolarizing graded potential because a hyperpolarizing graded potential causes the membrane potential to become inside more negative and, therefore, farther away from threshold (−55 mV).

Will an action potential occur in response to a hyperpolarizing graded potential that spreads from the dendrites or cell body to the trigger zone of the axon of a neuron? Why or why not?

mandible, parietal, sphenoid, zygomatic and occipital

With which bones does the temporal bone articulate?

ribs 2-10

With which ribs does the body of the sternum articulate?

smaller

Would the peak force of the second contraction in part (b) be larger or smaller if the second stimulus were applied a few milliseconds later?

no, because the epidermal layer is avascular

Would you expect an epidermal wound to bleed? Why or why not?

Thymine always pairs with adenine Cytosine always pairs with guanine

which bases always pair with each other